Drill-stem core bit and wall sampler



Sept- 29, 1 M. A. GARRISQN DRILL-STEM CORE BIT AND WALL SAMPLEIR 4 Sheets-Sheet 1 Filed Sept. 2, 1958 INVENTOR. MAR/o/v/I. GARE/601V Z y/v/v L. STEELE y Sept. 29, 1964 M. A. GARRISON DRILL-STEM com: BIT AND WALL SAMPLER Filed Sept. 2, 1958 v 4 Sheets-Sheet 3 INVENTOR.

MAR/0N ,4. GARP/SO/V BY y/v/v L STA-545 p 1964 M. A. GARRISON DRILL-STEM com: BIT AND WALL SAMPLER 4 Sheets-Sheet 4- Filed Sept. 2, 1958 INVENTOR. MA fP/OA/ A. mxscw United States Patent 3,159,727 DRILL-STEM CORE BIT AND WALL SAMPLER Marion A. Garrison, 2325 Monaco Parkway, Denver, Colo. Filed Sept. 2, 1958, Ser. No. 758,213 29 Claims. (Cl. 175-78) This invention relates to deep Well drilling, and more especially to apparatus for obtaining cores or samples from the side walls of well holes drilled by conventional bottom hole drill bits.

One object of the invention is to provide deep well drilling apparatus having means for taking cores from the side wall of a well hole without withdrawing the usual string of drill pipe from the hole, and to accomplish such results with coring apparatus contained in the drill pipe and readily installable therein and retrievable therefrom after a core has been out.

An important object of the invention is to provide means in such a coring apparatus for automatically withdrawing the core bit from the core hole and retracting it back into the drill stem at the end of the core cutting step.

A further object is to drive such a core cutting device by a novel positive displacement fluid motor operable by drilling mud forced into one side of the motor and dis charging from the other side.

An additional object is to provide for automatic retrac tion of the core bit from coring position at the will of the driller merely by control of the mud pressure at the top of the well.

Additional objects are to provide an improved fluid motor for the purpose, to provide an improved mounting for the motor in the drill string, to provide an improved connection between the motor and the core bit drive shaft, and to provide an improved core bit structure.

Other objects of the invention and the various features of construction thereof will become apparent to those skilled in this art upon reference to the following specification and the accompanying drawings forming a part hereof.

In the drawings:

FIG. 1 is an elevational view on a relatively small scale showing the lower portion of a drill pipe assembly equipped with a core bit and containing core bit actuating means within the pipe, the lower end of the assembly carrying a conventional bottom hole drill bit;

FIG. 2 is a fragmentary vertical section on an enlarged scale of the fluid motor contained within the lower portion of the drill pipe assembly hereof;

FIG. 3 is a cross section takenon the lines 3-3 of FIGS. 1 and 2 showing the motor construction and drivefluid inlets in the upper portion of the motor;

FIG. 4 is a cross section taken on the lines 4-4 of FIGS. 1 and 2 showing the motor construction and drivefluid outlets in the lower portion of the motor;

FIG. 5 is a cross section taken at the level of lines 3--3 of FIGS. 1 and 2, being similar to those of both FIGS. 3 and 4 to show the inlets of FIG. 3 and indicate in dotted lines the outlets from the two motor chambers at a lower level such as seen in FIG. 4, the outer casing being omitted;

FIG. 6 is largely a vertical elevational view and partly a vertical section showing approximately the upper half of the fluid motor and approximately the upper fourth of the retrievable coring unit as a whole, including the motor;

FIG. 7 is a view similar to and an extension from the lower end of that of FIG. 6 showing the lower half of the fluid motor and the upper portion of the extensible connection between the driven shaft of the motor and the core bit;

FIG. 8 is an extension from the lower end of FIG. 7

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and is largely a vertical section through the lower part of the mentioned extensible connection, showing also the valving construction and arrangement between the lower end of the motor driven shaft and the upper end of the flexible drive shaft for the core bit;

FIG. 9 is a cross sectional detail on the line 99 of FIG. 6;

FIG. 10 is partly a section and partly an elevational view constituting an extension from the lower end of FIG. 8 on the same scale;

FIG. 11 is partly a section and partly an elevation view constituting an extension from the lower end of FIG. 10 and showing approximately the normal position of the core bit on the lower end of its flexible drive shaft or tube in its retracted position at the mouth of the tubular curved guide which directs its angular movement through the side of the respective length of drill pipe in which the mouth of the guide is welded;

FIG. 12 is a view similar to that of FIG. 11 but showing the projection of the core bit into coring position at the desired angle of about 30 to the vertical;

FIG. 13 is a vertical section similar to that of FIG. 8 showing the relationship of the respective parts as the core bit is extended by the action of the pressure of the conventional drilling mud upon the piston provided by the lower cylinder head and its valve and plug parts, and indicating also the action and position of the reversing valve at the end of the coring stroke;

FIG. 14 is across section on the line 1414-of FIG. 13;

FIGS. 15 and 16 are vertical sections through upper and lower portions of a retrievable plug locked in place to. close the tubular guide against flow of drilling mud during normal drilling; and

FIG. 17 is a cross section on the line 1717 of FIG. 16.

Referring to FIG. 1, and also to FIGS. 6 to 11 as a vertical unit, the structure hereof is illustrated as being carried in the lower end of a drill pipe assembly which includes a bottom length of standard drill pipe 10 standing in a drilledwell hole 11, the lower end of the pipe 10 having threadedly attached thereto a shorter pipe section 12 commonly known as a sub and usually of somewhat smaller bore. The sub 12 in turn has threadedly attached to its lower end a longer pipe length 14 usually known as a drill collar to whose lower end a conventional drill bit 15 is threaded for typical rotary drilling of the well hole 11. Secured in the lower portion of the collar 14 immediately above the drill bit 15 is a curved tubular guide or guiding tube 16 (FIGS. 1, 11 and 12) whose lower end is welded at 17 to surrounding wall portions of a laterally directed hole in the side of the drill collar 14. The upper end of the guide 16 thus rigidly secured to the side of the collar 14 centers and supports a depending short supporting nipple or sleeve member 18 later to be described. The guide 16 receives the lower end of the core drilling unit hereof and guides a core bit later to be described into coring position as in FIG. 12.

The coring unit of this improvement is a retrievable elongated mechanism which might have an over-all length of seven or eight feet and an over-all diameter of 2 A to 2 /2 inches.

Such coring mechanism, when lowered into operative position as in FIG. 1, includes as principal parts: an elongated positive displacement fluid motor 20 (FIGS. 1, 6 and 7) disposed partly in the drill pipe length 10 and partly in the sub 12, and seated in a supporting sleeve 21 mounted in the upper end of the sub 12; a depending splined drive shaft 22 (FIGS. 1, 7 and 8) extending from the motor 20 down in splined relation into an advancing rotatably driven cylinder 24 to provide an extensible connection disposed in the sub 12 and the collar 14 at their 3 joint (FIGS. 7, 8 and 13); a reversing valve structure carried on the lower end of the drive shaft 22 withln the cylinder 24 (FIGS. 8 and 13 a reversing valve spring 26 within the cylinder 24 (FIGS. 7 and 8); an advancing piston or cylinder head structure 27 on the lower end of the cylinder 24 and carrying within it a control valve assemblage 28 (FIGS. 8 and 13); a flexible drive tube or shaft 30 attached to the under side of the piston and valve assemblage 27, 28 (FIGS. 8, 10 and 11) and operating as a piston rod driven by the piston 27 and its cylinder 24 to rotate and advance a sampling bit or core bit 32 (FIGS. 1, 11 and 12); and a positioning and guide sleeve combination of tube sections 34, 35 and 36 (FIGS. 8, 10 and l3) to center and position the flexible drive tube 30, the lower end of the lower sleeve 36 resting this sleeve combination on the upper end of the sleeve member or supporting nipple 18 mounted upon and centered by the upper end of the rigidly mounted curved guide tube 16. The tubular sleeve sections 34, 35 and 36 are welded together and to the supporting sleeve member or nipple 13 to produce a rigid vertical guide tube which extends above the curved guide tube 16 and serves to guide the extensible cylinder connection 24, its piston structure 27, and the flexible drive shaft 39 with its core bit 32 to and from core-cutting position as in FIG. 12. This rigid guide sleeve combination or assembly is suitably ported to conduct drilling mud down within the drill pipe assembly, and from the interior of the cylinder 24 and its piston 27 to the outside of the rigid sleeve combination 34, 35, 36, and thence to the usual mud passage through the drill bit 15.

Motor Structure The fluid motor 20 is operated by the usual drilling mud that is pumped down the drill string 10 under high pressure to lubricate the drill bit 15 and carry the cuttings up outside the drill pipe to the surface. The motor is provided with an upper housing cap or shell 40 having a reduced upper portion 41 (FIG. 6) which carries an upwardly projecting spearpoint 42 for engagement by a fishing or retrieving tool, the shank of the spearpoint being slidably mounted by a pin-and-slot connection and cushioned by a rubber shock absorber at 43. Appropriate mud-admitting ports 44 are provided in the upper portion of the cap 40 and lower ports 4411 are provided in the cap 40 to supply high-pressure mud from the bore of the drill pipe 10 to the motor interior. The motor comprises a main outer housing 45 over Whose upper portion the apertured cap 40 fits and to which the cap is threadedly secured at 46 immediately above its supporting sleeve 21. When the unit is lowered into the drill pipe assembly, splines 47 on the housing 45 immediately below the cap 40 enter splineways in the upper inner wall of the seating sleeve 21, thereby suspending the motor 20 and the rest of the coring unit in the drill pipe assembly in position to cut a core. The seating sleeve 21 is fixed in the upper end of the sub 12 by being threaded into the latter at 48 and being turned down against a stop shoulder thereof. It required, the seating sleeve 21 may be pro vided with longitudinal mud ducts 49 to by-pass drilling mud needed beyond that which is passed through the motor 20.

Within the motor housing 45, there is mounted an axially extending rotor 50 (FIGS. 2 to 7) which is rotated in the direction of the short curved arrows of FIGS. 3 and 4 by drilling mud entering the upper portion of the motor from the interior of the cap 40 by way of a vertically extending, diametrically opposed pair of angularly directed inlet ports 51 (FIGS. 3, 5 and 6) through the wall of the motor housing 45 above the threads 46. The pressurized mud enters two vertical chambers 52 between the motor housing 45 and the rotor 50 and works against four vertical folding rubber vanes or blades 53 extending substantially the length of the rotor 56 and disposed in corresponding vertical channels in the rotor surface so that their outer halves flex between extended driving positions and fully collapsed positions within the channels when passing diametrically opposed vertical separator strips 54 that divide the space between the rotor and the housing 45 into two equal vertical chambers having substantially the length of the rotor. The inner vert1cal halves of the vanes 53 are secured in the bottoms of the mentioned vertical channels by means of screws 55 and thin flat retainer strips 56, and the relatively thick flat separator strips 54 are secured to the inner wall of the motor housing 45 by screws 57. Preferably the swinging flap halves of the veins 53 are reinforced by thin metal insert strips 58 which may be vulcanized in place. The rubber of these vanes is preferably an oil-proof synthetic type, such as neoprene, as is true of all other rubber parts of the present structure.

The pressurized drilling mud entering the inlet ports 51 passes downward in the described vertical motor chambers 52 and by reason of the application of its pressure against the extended vanes 53 causes rotation of the rotor 51). Below the region of the splines 47 and the seating sleeve 21, a vertical series of vertical outlet ports 60 is provided in the motor housing wall for each of the two vertical chambers 52 so that there is maximum pressure drop in the venting drilling mud as it leaves the motor through the housing 45. These outlet ports 69 are at the opposite sides of the respective chambers 52 from the inlet ports 51. Thus, each inlet port 51 is close to the adjacent separator strip 54, and the respective series of outlet ports 60 is over at the opposite side of the respective chamber 52 and near the opposite separator strip 54. Thus, mud travelling down through the motor 20 is divided into two effective streams simultaneously working against diiferent vanes 53.

The upper end of the rotor 50 is rotatably mounted in the motor housing 45 by means of a bearing 62, and is connected at its lower end with the drive shaft 22 by a flexible joint or drive connection 64 (FIG. 7) just below the lower end of the motor housing 45. The bearing 62 comprises a lower bearing nut 65 threaded into the top of the motor housing 45 (FIGS. 2 and 6) and lined with a bonded hard rubber bearing sleeve 66 (preferably about Shore hardness neoprene) extending over the top of the bearing nut 65 to form a bearing flange and fluted as indicated to pass a bit of drilling mud for lubrication horizontally on the flange surface and vertically within the bearing. Upon the top of the rotor 50 there is fixedly threaded an upper bearing nut 67 which rotates upon the flange of the bearing sleeve 66, the upper end of the rotor having a reduced diameter as shown to pass up through the lower bearing member 65, 66 as shown. Between the nut 65 and the upper shoulder of the rotor 58 an end plate or washer 68 is placed, and between the reduced stem of the rotor and the rubber sleeve 66 a sleeve bushing 69 is provided, the latter preferably extending upward into a shallow pocket in the under side of the upper bearing nut 67.

Secured on the upper end of the rotor 50 is a lock nut 76 which carries on its top a cap screen 72 that intercepts large cuttings that may have passed the ports 44 and 44a, such screened mud now passing into a central bore 73 in the rotor 50 and continuing on down through the flexible drive connection 64 and through the rotated drive shaft 22 past the reversing valve 25 and into the bottom of the cylinder 24 against its piston structure 27. This is the pressure mud supply which advances the core bit 32, such action resulting from the operation of the mechanisms of FIGS. 7, 8 and 13.

The mounting of the lower end of the rotor 50 (FIGS. 2 and 7) in the bottom of the motor housing 45, which mounting is just above the drive connection or coupling 64, is largely a reversal of the bearing mounting at the top of the motor 20. Thus, a lined bearing nut 75 having a flanged rubber liner 76, like the bearing 65, 66, is threaded in an inverted position up into the bottom of the housing 45 against an end plate or packed thrust washer 77 disposed about the lower shouldered reduced end of the rotor 50. A sleeve bushing 78 is used within the rubber liner 76 as with the upper bearing liner, and a pressure nut 79, as presently to be described, is used against the flange of the rubber liner and is positioned about the adjacent projecting end of the bushing. These flanged rubber liners 66 and 76 serve to impart a desirable although limited amount of flexibility in the resultant joints, as an inspection of FIGS. 6 and 7 indicates.

The Extensible Drive Connection The coupling or drive connection 64 between the lower end of the rotor '50 and the rotating drive shaft 22 includes a coupling housing 80 whose lower end is threaded onto the upper end of the drive shaft 22 in driving relation and whose upper end is fixed to the lower end of the rotor 50 through the medium of a coupling bushing 82 set into a corresponding pocket in the upper end of the housing 80 and bonded to the latter with a cup-like flexing rubber drive joint 83 bonded to the opposing walls of the housing and the bushing and providing an adequate driving joint with a limited amount of flexibility. A set screw 84 seated in the bushing 82' is located in a slightly oversize hole 85 in the housing 80 to permit a little play during rotary driving and yet prevent shearing of the rubber drive joint 83. The upper end of the bushing 82' is internally threaded to receive the lower end of the rotor 50 in driving relation. The projecting upper end portion shown of the bushing-82 is externally theaded to receive the previously mentioned jam nut or pressure nut 79'and also a locknut 86 therefor. Both the coupling housing 80'and the bushing 82, as well as the rubber joint 83, are provided with axial bores at 87 to pass pressurized mud flowing through the rotor 50 and the drive shaft 22. Desirably the inner end of 'the bushing 82 is headed as shown so that it will just pass through the central opening left in the top of the housing '80 by an inturned flange 88 which further confines the rubber drive joint 83, as illustrated.

As best seenin FIG. 7, driving of the depressible or extensible cylinder 24 by the drive shaft 22 is effected by splines which extend the length of the shaft 22 and engage in splineways in an upper cylinder head 90 threaded into the top of the cylinder 24, as seen'at 91. As shown, the top of the head 90 overhangs the cylinder 24 in flush relation, and carries bolts 92 which engage and pull up a splined ring retainer 93 to compress spline packing 94; the retainer 93 also providing a seat for the top of the reversing spring 26. V

The lower extremity of the splined drive shaft 22 is machined smooth below the splines to accommodate the previously mentioned sliding sleeve valve as seenin FIGS. 8 and 13, and its extreme tip is threaded to receive externally the upper end of an internally threaded rod cap 95 whose recessed lower end is also a carrier for locking balls 96 received in ball sockets, as best seen in FIG. 13, for locking the cap 95 and consequently the drive shaft 22in a lower cylinder head 98 fixedly threaded on the lower end of the advancing cylinder 24, as best seen in FIG. 8. This cylinder head 98, which is itself generally cylindrical in form, is a part of the previously mentioned advancing piston structure 27, and, with its contained parts, is separately seen in FIG. 3 where it is' more apparent that it functions as a piston for the core tube (see also FIG. 10) to force the latter downward piston-fashion.

Under normal or non-operating circumstances, the balls 96, which are always in their opposed sockets, are disposed down in the cylinder head 98 as shown in FIG. 8 where they are forced radially outward into locking position in an annular detent groove 99 seen in FIG. 13. This locking position is ei fected and maintained by engagement of the balls 96 by an upstanding sleeve-like nipple 100a formed at the upper end of a lock-and-release until accumulating pressures overcome the mechanism within the cylinder head 98 and heretofore referred to generally as the control valve assemblage 28.-

Meanwhile, the rod cap being locked in the cylinder head 98, the cylinder 24 and its cylinder head 98 cannot be depressed to advance the core bit 32. Under these conditions the sliding sleeve valve 25 is in its upper position on the lower end of the drive shaft 22, as seen in FIG. 8, where it closes upper ports 104 in the end of the drive shaft which communicate with a longitudinal bore 105 in the drive shaft that in turn receives a drilling mud supply from the bore 73 of the rotor shaft 50 as previously indicated. At this time, assuming drilling mud is being pumped through the drill pipe, pressurized mud reaching the bores 73 and 105 passes through another pair of ports 106 below the ports 104 and the sleeve valve 25 and into an annular space 107 within the upper cylindrical end of the cylinder head 98, below the sleeve valve 25 and above the rod cap 95 and the lock-and-release piston 100. While pressure mud might pass directly from the bore 105 through the ports 106 to the annular space 107, it is important and certainly preferable that, because of the normal high operating pressures, the flow be restricted, and for this purpose a fiow bean 108 is used which is a small ported cylindrical rod section fitting into the bottom portion of the bore 105 and retained by the rod cap 95. This porting 108a, in the form used, is a small vertical bore leading down from the topof the rod andcornmunicating with a branching or cross channel communicating with the indicated lower ports 106 as seen in both FIGS. 8 and 13.

When mud is being pumped at the surface, and the present apparatus has been positioned in the drill pipe assembly as indicated, the balls 96 initially lock the cylinder head 98 (along with the driven cylinder 24) to the lower end of the drive shaft 22, the sleeve valve 25 being in its upper position, as seen in FIG. 8, where its inner and outer packing rings 109 seal off mud flow along the inner wall of the cylinder 24 and from the ports 104. This is also the position of the parts when the apparatus is being lowered into the hole, whether on a line or by being circulated down into position by the mud.

Drilling Mud Action When mud pumping gets under way for the purpose of cutting a core, mud coming down past the motor 20 and from its outlet ports 60 and along the outside of the depressible actuating cylinder 24 reaches the inside of the upper member 34 of the guiding sleeve combination 34, 35', 36 within the upper portion of the drill collar 14, whence the mud passes through ports 110 into the drill collar 14 and down outside the sleeve combination 34, 35, 36, whence it passes down past the centering nipple 18 and the curved guide tube 16 to the usual mud bore through the main drill bit 15.

Mud which passes down the bores 73 and 105 of the rotor 50 and the splined drive shaft 22, at this stage reaches the annular space 107 below the sleeve valve 25 via the bean ports 108a and the lower ports 106 in the end of the drive shaft-22. This action creates mud pressure working across the advancing piston structure made up of the cylinder head 98 and contained parts including the lock-and-release piston 100 and other parts of the mentioned control valve assemblage 28, especially a relief valve 112 contained within release piston 100 and closing, under influence of a spring 113, against an annular seat 114 (FIG. 13) around the base of the port through the hollow nipple 100a. This relief valve 112 and its spring 113 act to insure substantially constant pressure on the core bit, excess pressure mud being vented past the seat 114 and radially through ports 114a in the release piston 100 when the valve 112 opens, passage to the outside of the sleeve member 35 being provided by ports 115 therein and ports 116 in the lower adjacent wall of the cylinder head 98. For constant relief of excess pressure, when the valve 112 does not open, a flow bean 118 with a constantly open port is mounted in the top of the valve 112.

As pressure builds up on the indicated parts of the cylinder head 98, the point is reached where the release piston 100 overcomes its seating or loading spring 102 and is forced down to trip or withdraw its nipple 100a from the lock balls 96 so that the latter release the cylinder head 98 to permit it to be moved down in the sleeve combination 34, 35, 36 to advance the core bit 32. The spring 102 controlling the release piston 10% is disposed. about the lower reduced end of a plug 120 whose upper end is threaded into the lower portion of the piston 100 below its ports 114. The upper end of the plug 120 acts: as a seat for the lower end of the relief spring 113 whoseupper portion is contained in a well within the lower part. of the body of the relief valve 112. The lower end of the: release piston spring 102 is seated in a well in the upper portion of a plug 122 threaded into the lower end of the cylinder head 98. Surge ports 123 leading to the well of the plug 122 provide for necessary mud displacement as: the release piston plug 120 moves against its spring 102..

By these means, varying mud pressures are adequately' regulated and the cylinder head 98 and its advancing: cylinder 24 are unlocked from the balls 96 when, and only when, mud pressure has built up in the apparatus to operate the rotor 50 of the motor and thereby rotate: the splined drive shaft 22 and the depressible cylinder 24 to advance the latter, its head 98 and the core bit 32. Meanwhile the lock balls 96 will have maintained the assembly.

Corz'ng When the advancing and actuating cylinder 24 is driven by the splined shaft 22, the core bit 32 is rotated from the lower end of the cylinder head 98 by way of the plug 122 and the flexible core-driving tube 30. The tube is bound to the lower end of the driven plug 122 by a tubular coupling 125, threaded onto such plug (FIGS. 8 and 10), and a coupling sleeve 126 whose upper end is threaded onto an intermediate portion of the coupling 125. The opposing portions of the coupling 125 and its sleeve 126 are threaded to receive and clamp between them the upper end of the flexible tube 30 which desirably is a braided wire hose embedded inside and outside in rubber material like neoprene. Internally this hose is reinforced with a steel spring wire coil 128 whose upper end abuts against the end of the coupling 125. Desirably this spring is square in cross section. The lower end of the flexible drive tube 30 is mounted in the same way as its upper end by means of identical tubular coupling 130 and coupling sleeve 131, the lower end of the spring coil 128 abutting against the end of the coupling 130 which in turn is threaded at 132 onto the upper end of the core bit 32. The outer end of the core bit may be dressed with crushed tungsten carbide or the like as illustrated at 133. Internally, the core bit carries any conventional or preferred core catcher 134 and externally it carries an expendable tough rubber protecting sleeve tip 135 which protects the grinding end of the bit 32 as it is lowered into the guiding sleeve combination 34, 35, 36, 18 and the curved guide tube 16 in its travel all the way down the drill string 10 from the surface, whether on a line or by being circulated down in the drill mud. If desired, and preferably, the bottom surface portion 136 at the end of the guide tube 16 is lined with wearing material which also facilitates rupture of the protecting sleeve tip 135 which is in any event disintegrated when the bit starts grinding in the formation as in FIGS. 1 and 12. As indicated in FIG. 11 the curving portion of the guide tube 16 is necessarily elliptical in cross section to accommodate movement of the core-driving tube 30 and the core bit 32.

General Operation When it is required to obtain a core from the side of the well hole as indicated in FIGS. 1 and 12, the assembled retrievable coring tool is run into the drill string 10. This tool includes the rotary fluid motor 20 having the manipulating spear point 42 at the top thereof, the splined drive shaft 22, the advancing and actuating cylinder 24 driven by the shaft 22, the flexible core-driving tube 30, and the core bit 32. The tool may be lowered on a line or it may be introduced into drilling mud in the drill string and circulated to its seat in the sub 12 and the drill collar 14 where the core bit 32 assumes the position seen in FIG. 11 ready for projection to drill a core at an angle of about 30 to the vertical as seen in FIG. 12. The balls 96 are in locking position.

Commencement of pumping of drilling mud at the surface causes such pressurized mud to enter the inlet ports 51 of the motor 20 (FIG. 6) and leave the outlet ports 60 (FIG. 7) thereby turning the rotor 50 therein (FIGS. 2 to 5 and 7) and driving the splined shaft 22 to rotate the actuating and advancing cylinder 24 through its top cylinder head and in turn rotate its bottom cylinder head 98 which is connected through its lower plug 122 to drive the flexible tube 30 and the core bit 32 on its lower end.

Up to this stage the locking balls 96 have retained the rod cap on the lower end of the splined drive shaft 22 locked in position in the lower cylinder head 98, so that the actuating cylinder 24 and its head 98 cannot move down on the splined shaft 22, the balls being held by the upstanding nipple 100a (FIG. 13) on the top of the lock-and-release piston 100.

When the tool is properly seated as above indicated and drilling mud is being pumped under pressure to turn the rotor 50 and the core bit 32, the parts are ready for advancement of the cylinder 24 and the core bit. Under these conditions, the mud stream advancing through the bores 73 and of the rotor 50 and the shaft 22 passes out the ports 106 at the lower end of shaft 22.

As previously described, mud pressure through the ports 106 builds up under the sleeve valve 25 (whose upper end abuts the lower ends of the splines of the shaft 22) and is therefore exerted against all the upper portions of the cylinder head 98 and of the lock-and-release piston 100 (through adequate passageways which exist around and between the parts). The result of such pressure is to depress the release piston 100 and withdraw its nipple 100a from between the lock balls 96 which now move slightly radially inward in their seats in the lower end of the rod cap 95 (as indicated in FIG. 13) and free themselves from the detent groove 99 in the adjacent inner wall of the cylinder head 98.

The applied mud pressure now forces down the cylinder head 98 and, with it, the rotating actuating cylinder 24, as well as the flexible core-rotating drive tube 30 and the core bit 32. Thus the core bit is projected against the wall of the well hole and the rotary cutting of a core commences, as indicated in FIG. 12. The protective rubber cap is quickly disintegrated and discarded, and the core being cut passes up into the core catcher 134.

As the core cutting operation continues, the upper cylinder head 90 moves toward the sleeve valve 25 and gradually compresses the reversing spring 26 against the valve 25 until the spring pressure combined with the mud pressure working on the lower cylinder head 98 overcomes the mud pressure working against the under side of the sleeve valve 25 and moves the latter down on the lower end of the shaft 22 from its position shown in FIG. 8 to the position of FIG. 13. This movement covers the lower ports 106 in the shaft 22 and uncovers the upper ports 104, so that the mud pressure is now out off from the lower cylinder head 98 and applied against the under side of the upper cylinder head 90 to return the latter up to its original position approximately and withdraw the core bit 32 and its core back into the guide tube 16.

The length of the reversing spring 26 and its power are such that they determine the length of the stroke of the cylinder 24 and the length of the core that is cut. Suitable small vents 140 (FIGS. 7 and 8) in the cylinder 24 act as surge ports for adequately preventing mud trapping within the cylinder.

When the reversing valve sleeve 25 is tripped and the travel of the core bit 32 is reversed, the pressure on the mud pump at the top of the well falls off about and this is notice to the driller that the cycle has been completed. The driller now runs in a line with an overshot to engage the spear point 42 and withdraws the core cutting assembly from the drill pipe with its core. Another core may now be taken at a higher level by lifting the drill pipe, or at the same level by rotating the drill pipe to another circumferential position. Such cores or samples may be takenanywhere in the hole, the full size drill bit serving always to center the string and position the coring tool.

Should it develop that coring is not proceeding rapidly enough, thus signifying for example that the core bit is dull, the driller may retract the core bit 32 without waiting for a full cycle to be completed. This he does by stopping mud circulation for a short interval, for example about thirty seconds, until pressure is equalized in the bottom of the hole. This allows the reversing sleeve valve to assume its retracting position under influence of the partially compressed reversing spring 26. Upon starting the pumps again, the core drill is retracted as before and may be pulled up to the surface for inspection. Thus, movements of the coring tool are always under the positive control of the driller.

Retrievable Drilling Plug When it is desired to drill at the bottom of the well hole with a usual drill bit 15, loss of drilling mud through the curved guide tube 16 is prevented by means of a drilling plug 150 shown in FIG. 16 mounted on the lower end of a latch-carrying body 152 having at its upper end a retrieving spear point 153. The plug 150 is desirably of neoprene or similar rubber-like material and of a size to fit into the upper end of the guide tube 16 sufiiciently well to prevent passage of significant amounts of drilling mud during ordinary drilling. The upper end of the plug 150 is. vulcanized or otherwise suitably bonded to the corrugatedlower tip 152a of the hollow body 152. Pivoted between the sides of the body 152 on a pivot pin 154 is an upstanding latch 155 whose upper end has a latch head 156 adapted to catch under an annular shoulder 158 formed in the inner wall of the lower portion of the sleeve member 36 just above the telescopic welded joint 159 between the sleeve members 18 and 36. The top of the latch 155 is urged into latching position by a spring 160 having one end seated in a pocket in the latch top and its other end positioned by a set screw 161 in the body 152.

To withdraw the latch head 156 from the shoulder 158, a withdrawing pin 162 is mounted in a slot 164 in the latch 155 to engage a cam wall 165 thereof, so that when the pin 162 is lifted the latch head 156 is retracted. The pin 162 is carried in the lower end of a forked link 166 whose upper end is threaded and pinned to the lower endof an elongated stem 168 that carries at its top, by a pin and thread connection, an upper socket member 170 which receives and carries the lower end of the spear point 153 by a pin-and-slot mounting 171.

Secured to the upper end of the hollow body 152 by a threaded connection seen in FIG. 15, and disposed about an intermediate portion of the stem 168, is a pressurebalancing cylinder 172 having an elongated pocket 174 in its upper end for reciprocation of a packed piston ele ment 175 formed on the middle portion of the elongated stem 168 and about which the cylinder 172 is mounted and packed. Extending upward from the lower end of the stern 168 where it opens between the forks of the link 10 166 is an axial bore 176 that communicates through ports 178 with the pocket 174 at the top of the piston element 175. A spring 179 is used about the lower endof the stem 168 to keep the stem 168, the link 166 and the lift pin v162 in depressed position, the lower end of this spring 179 bearing against the top of the link 166 and the upper end of the spring 179 bearing on the top of a pocket in the lower .end of the cylinder 172.

The top of the pocket 174 inthe top of the cylinder 172 is closed by a packed cap 180 screwed on the top of the cylinder 172 to provide a closed working cylinder for the piston element 175. Such pocket 174 is, however, vented by the ports 178 and the bore 176 above the piston 175 and by a surge port 181.below the piston 175, the surge port 181 opening immediately above an. annular seatingshoulder 182 on. the external wall of the pressure balancing cylinder 172, where adequate leakage space exists thereabove. The shoulder 182 faces downward and bears upon anupwardly faced complementary supporting shoulderon the inner wall of the sleeve element 36 .fixed in the drill collar 14.

Thus, the plug and itssupporting body member 152 are supported in operative position in the sleeve member 36 by the shoulders at 182 and are prevented from. being forced upward by the latch head 156 of the latch when engaged under the downwardly facing shoulder 158 in the lower part of the sleeve member 36.

However, when a fishing tool or overshot is run down to grip the spearpoint 153 and upward draft is applied, the stern 150 is lifted to lift the latch-withdrawingor trip pin 162, and the latch 155 and its head 156 are withdrawn for removal of the plug 150.

The piston 175, the spring 179, the pocket 174 and the bore 176 in the stem 168 communicating therewith provide, a hydraulic balancing means acting as a dashpot to prevent the drilling plug 150 from becoming unlatched and driven upward in the drill pipe under influence of high 1 pressure mud surges which otherwise would act on the lower end of the stem 168 as a piston and push it upward to lift the link 166 and cause release of the latch head 156. Surges from below can be due to a number of reasons such as mud pump surges, but the most common reason is rapid lowering of the drill pipe (with the plug 150 in place) when running the drill string back into the hole. Modern deep well rigs are very powerful and are equipped with very powerful brakes. This permits the driller, when he wishes to run the pipe and drill bit back to the bottom of the hole, to go in at a very rapid rate. With the hole full of heavy drilling mud, such rapid lowering builds up high pressures from below, and these work against the link 166 and the bottom of the stem 168 to release the latch. As now desirably designed, the area of the piston element is more than double the area of the stem 168. Since pressure surges are introduced into the chamber 174, through the bore 176 and the ports 178, the downward pressure offsets the upward pressure, and the surges cannot withdraw the latch and unlatch the plug. The plug 150 can be released only by an upward pull on the spear point 153, as above described.

What is claimed is:

1. In combination in a deep well core-drilling apparatus:

a drill pipe assembly having at its lower end means for attachment of a bottom hole bit for drilling a well hole;

a tubular curved guide in a lower portion of said pipe assembly to receive and guide a core bit laterally outward and downward at an angle through a side wall of said pipe assembly to engage the side wall of a well hole drilled by said bottom hole bit;

a core drill bit rotatably mounted in said guide;

a fluid-driven motor retrievably received in said pipe assembly above said tubular guide and having a driven member;

an extensible driving connection between said driven member and said core bit;

means providing for passage of drive fluid through said pipe assembly and said motor and driven member;

piston means in said extensible driving connection and disposed in the path of said drive fluid to advance said core bit in said guide;

valve means on said driven member and controlling fluid ports in said driven member to pass drive fluid to said piston means of said connection;

and pressure means in said connection energizable by movement of said connection and its piston means and bearing upon said valve means to shift the latter upon predetermined energizing movement for closing ports passing drive fluid to said piston means advancing said core bit, and opening ports passing drive fluid to said connection to reverse its movement and retract said core bit.

2. A combination as in claim 1 including a cylinder carrying said piston means and disposed about said driven member and enclosing said valve means, the upper portion of said cylinder receiving said fluid to reverse said movement and its upper end serving as a reversing piston.

3. A combination as in claim 2 wherein said pressure means is a spring within said cylinder and about said driven member.

4. In combination in deep-well core-drilling apparatus:

a length of drill pipe for drilling a well hole;

a curved hollow guide in a lower portion of said pipe;

a core drill in said guide;

an elongated motor in an upper portion of said pipe;

an extensible driving connection between said motor and said core drill and extending from said motor to said guide to advance said core drill;

piston means in said connection to advance the latter;

conduit means for applying pressurized drilling fluid from said drill pipe to said piston means;

valve means adjacent said piston means to shift flow of drilling fluid to reverse movement of said piston means and retract said core bit;

and pressure accumulating means to actuate said valve means.

5. A combination as in claim 4 wherein said pressure accumulating means is a spring energized by advance of said piston means.

6. A combination as in claim 4 wherein said driving connection includes a fluid conducting drive shaft having a lower end terminating adjacent said piston means, and said valve means includes a sleeve valve controlling ports in said shaft end.

7. A combination as in claim 6 wherein releasable locking means is provided between the lower end of said shaft and said piston means, and pressure actuated means is connected with such locking means to release the latter.

8. A combination as in claim 6 wherein said extensible driving connection includes also a cylinder having an upper cylinder head receiving said shaft in driving relation and said reversing fluid in retracting relation, said cylinder having a lower head providing said piston means.

9. In combination in deep-well coring apparatus:

a hollow drill pipe assembly having means for mounting a bottom-hole drill bit on the lower end thereof;

a curved guide in a lower portion of said assembly leading to a hole in the side of said assembly to direct a core drill to said side hole;

a core drill movable in said guide to said hole;

a fluid-driven motor retrievably positioned in said assembly above said guide and providing a rotatably driven member;

piston means connected with and rotatably driven by said motor-driven member and movable downward in said assembly and with respect to said motor;

means connecting said piston means with said core drill to rotate and advance the core drill through said side hole;

and valve means on said driven member movable for opening and closing ports in said driven member and passing driving fluid to said piston means to advance the core drill to said hole and to cut off such fluid and reverse fluid flow for reversing movement of the piston means to retract said core drill.

10. A combination as in claim 9 wherein said motordriven member is a drive shaft carrying driving fluid to said valve means and said piston means.

11. A combination as in claim 9 including releasable locking means between said driven member and said piston means, and means responsive to applied fluid pressure to release said locking means for permitting advance of said piston means.

12. In combination in deep-well coring apparatus:

a drill pipe assembly having means at its lower end for attaching a well-drilling bit;

a guide in a lower portion of said assembly leading to a side hole therein;

a core drill in said guide movable to said side hole;

a fluid-driven motor retrievably mounted in said assembly above said guide and having a depending rotatably driven shaft;

a cylinder into which said driven shaft depends;

an upper cylinder head fixed at the top of said cylinder and having driving sliding connection with said shaft;

a lower cylinder head fixed at the lower end of said cylinder and having a mechanical longitudinal-thrust driving connection with said core drill;

said shaft providing a drilling fluid passage;

fluid control means adjacent the lower end of said shaft to direct fluid from said passage to the top of said lower cylinder head for depressing the cylinder along said shaft;

fluid passing means in said lower cylinder head for conducting drilling fluid from the lower end of said cylinder to reduce pressure in the latter;

and spring means responsive to the fluid pressure in said cylinder and located adjacent said fluid passing means for regulating the pressure in said cylinder.

13. In combination in deep-well coring apparatus:

a drill pipe assembly having means at its lower end for attaching a well-drilling bit;

a guide in a lower portion of said assembly leading to a side hole therein;

a core drill in said guide movable to said side hole;

a fluid-driven motor retrievably mounted in said assembly above said guide and having a depending rotatably driven shaft;

a cylinder into which said driven shaft depends;

an upper cylinder head fixed at the top of said cylinder and having driving sliding connection with said shaft;

a lower cylinder head fixed at the lower end of said cylinder and having driving connection with said core drill;

said driven shaft having a bore to feed pressurized drive fluid to said lower cylinder head to act as a piston to advance said core drill, said shaft having ports at its lower end spaced at two levels, a lower port feeding fluid to said lower cylinder head to act as a piston to advance said core drill, and an upper port feeding fluid to said upper cylinder head;

and a valve movable at the lower end of said shaft to cover said ports selectively to direct pressurized fluid up and down selectively to retract and advance said core drill selectively.

14. A combination as in claim 13 including releasable locking means between the lower end of said driven shaft and said lower cylinder head, and pressure-responsive means to release said locking means for advance of said cylinder.

15. A combination as in claim 13 including pressure accumulating means within said cylinder to bear upon said valve to shift the valve upon predetermined pressure accumulation.

16. A combination as in claim wherein said pressure accumulating means is a spring disposed about said depending driven shaft and energizable by said upper cylinder head as said cylinder is moved to advance said core drill.

17. In combination in deep-well coring apparatus:

a drill pipe assembly having means at its lower end for attaching a Well-drilling bit;

a guide in a lower portion of said assembly leading to a side hole therein;

a core drill in said guide movable to said side hole;

a fluid-driven motor retiievably mounted in said assembly above "said guide and having a depending rotatably driven shaft;

a cylinder into which said driven shaft depends;

an upper cylinder head fixed at the top of said cylinder and havingdriving' sliding connection with said shaft;

a lower cylinderheadfixed'at the lower end of said cylinder and having driving connection with said core drill;

releasable locking means between the lower end of said driven shaft and said lower cylinder head;

said shaft having passage means supplying pressurized drive fluid tosaid lower cylinder head to act as a piston to advance said core drill;

and pressure-responsive means to release said locking means for advance of said cylinder.

18. A combination as in claim 17 wherein said pressure-responsive means to release said locking means is a spring-pressed cylinder disposed in said lower cylinder head.

19. A combination as in claim 18 including a ported spring-pressed flow equalizer carried in said springpressed cylinder to open and by-pass excess pressure fluid.

20. In combination in deep-Well coring apparatus:

a drill pipe assembly having means at its lower end to carry a well-drilling bit;

a core-bit guide in a lower portion of said assembly leading to a side hole in the assembly;

a core bit in said guide to be moved to said slide hole;

a fluid-driven motor retrievably disposed in a mounting in said assembly above said guide;

a depending shaft rotatably driven from said motor;

a depending cylinder into which said driven shaft depends in splined relation for rotation of said cylinder and downward advancement of said cylinder;

piston means carried at the lower portion of said cylinder for rotation thereby and having a mechanical longitudinal-thrust driving connection with said core bit;

means for supplying pressurized drive fluid to said motor and said piston means;

and hydraulically releasable ball locking means subject to the fluid pressure and located between the lower end of said drive shaft and said piston means to hold said piston means and cylinder against downward movement relative to said motor-driven shaft, said piston carrying a pressure responsive member engaging said ball means to maintain locking engagement of said ball means and releasable by said pressurized drive fluid to release said ball means.

21. In combination in deep-well coring apparatus:

a drill pipe assembly having means at its lower end to carry a well-drilling bit;

a core-bit guide in a lower portion of said assembly leading to a side hole in the assembly;

a core bit in said guide to be moved to said side hole;

a fluid-driven motor retrievably disposed in a mounting in said assembly above said guide;

a depending shaft rotatably driven from said motor;

2. depending cylinder into which said driven shaft depends in splined relation for rotation of said cylinder and downward advancement of said cylinder;

piston means carried at the lower portion of said cylin- 14 der for rotation thereby and having driving connection with said core bit;

means for supplying pressurized drive fluid to said motorandfluid directing means to supply pressure fluid to said piston means;

and a slidable ported spring-pressed flow equalizer cartied 'insaid piston means to open and by-pass excess pressure fluid.

22. In combination in deep-well coring and drilling apparatus:

a drill pipe assembly having means at the lower end for mounting a well drilling bit;

guide means in the lower end of said assemblyleading to a side hole for laterally passing a core drill and adapted for holding a plug;

mounting "means in an upper portion of said assembly for mounting a fluid driven motor connected to rotate a. core drill in said guide means;

seat means associated with said guide means to position a plug in said guide means when said motor and core drill are removed; the lower portion of said assembly having a plug retaining shoulder;

a plug in said seat means having a releasable retaining catch mounted at its upper portion to engage said plug-retaining shoulder;

and a retrieving stem in said plug connected to said catch to retract said catch, said plug having in its upper portion a dash-pot cylinder, and said stern having a bore communicating a chamber adjacent said catch with said cylinder, and a dash-pot piston Working in said cylinder whereby to restrict high pressure drill mud action against said stem.

23. A combination as in claim 22 including a core drill mountable in said guide means to be rotated and advanced therein by said motor, said plug and said core bit being interchangeable in said guide means for drilling a core by said core bit and motor, and for plugging said guide means by said plug for drilling with said drill pipe assembly and said well drilling bit at the bottom of a well hole.

24. In a deep-well coring apparatus:

a length of drill pipe;

a curved guide in a lower portion of said pipe;

a core drill movable in said guide;

an elongated motor above said guide;

extensible driving means between said motor and core drill to advance the latter;

piston means and cylinder means in said driving means;

said driving means providing conduit means for applying pressurized drilling fluid from said drill pipe to said piston means and the lower portion of said cylinder means; and

valve means adjacent said piston means and said driving means, the lower portion of said driving means having port means adjacent said valve means, said valve means being movably mounted adjacent said lower portion to shift drilling fluid flow from the lower portion of said cylinder means.

25. Apparatus as in claim 24 including pressure accumulating means in said cylinder means to actuate said valve means in one direction.

26. In a deep-well coring apparatus;

a length of drill pipe;

an elongated motor in an upper portion of said pipe;

a guide in a lower portion of said pipe;

a core drill movable in said guide;

an extensible driving connection between said motor and said core drill and including a drive shaft depending from said motor and a cylinder into which said shaft depends in driving relation;

piston means at the lower end of said cylinder;

said driving connection providing conduit means for applying pressurized drilling fluid from said drill pipe to said piston means to lower said cylinder; and

pressure accumulating reversing spring means between said piston and the upper portion of said cylinder.

27. Apparatus as in claim 26 including valve means adjacent said drive shaft and in said driving connection to direct fluid into the lower portion of said cylinder, and to reverse fluid flow for returning the cylinder upward.

28. Apparatus as in claim 26 including releasable means between the lower end of said drive shaft and said piston, and means to release said releasable means for advance of said piston.

29. In combination in deep-well coring apparatus:

a hollow drill pipe assembly having means for mounting a bottom-hole drill bit on the lower end thereof;

a curved guide in a lower portion of said assembly leading to a hole in the side of said assembly to direct a core drill to said side hole;

a core drill movable in said guide to said hole;

a fluid-driven motor retrievably positioned in said assembly above said guide and providing a rotatably driven depending fluid-carrying shaft having ports adjacent its lower end;

a cylinder driven by said shaft and into which said shaft depends;

piston means connected with and rotatably driven by said cylinder and movable downward in said assembly and with respect to said motor;

valve means on said shaft adjacent said ports and movable by applied fluid pressure to open one port while closing another to apply fluid pressure to advance said piston and cylinder and reversible by pressure accumulation above said valve to open another port for reversing said piston means and cylinder;

and means connecting said piston means with said drill to rotate and advance the core drill through said side hole.

References Cited in the file of this patent UNITED STATES PATENTS 557,686 Meissner Apr. 7, 1896 731,639 Walter June 23, 1903 2,176,375 McClinton Oct. 17, 1939 2,198,016 Rogers et a1. Apr. 23, 1940 2,227,233 Scott et al. Dec. 31, 1940 2,267,833 McMahan Dec. 30, 1941 2,296,161 Hall Sept. 15, 1942 2,324,682 De Long July 20, 1943 2,358,470 Oswald Sept. 19, 1944 2,409,811 Taylor et a1 Oct. 22, 1946 2,594,292 Cornelius Apr. 29, 1952 2,776,817 Gregory et al. Jan. 8, 1957 2,783,844 Kanady Mar. 5, 1957 2,852,230 Garrison Sept. 16, 1958 

24. IN A DEEP-WELL CORING APPARATUS: A LENGTH OF DRILL PIPE; A CURVED GUIDE IN A LOWER PORTION OF SAID PIPE; A CORE DRILL MOVABLE IN SAID GUIDE; AN ELONGATED MOTOR ABOVE SAID GUIDE; EXTENSIBLE DRIVING MEANS BETWEEN SAID MOTOR AND CORE DRILL TO ADVANCE THE LATTER; PISTON MEANS AND CYLINDER MEANS IN SAID DRIVING MEANS; SAID DRIVING MEANS PROVIDING CONDUIT MEANS FOR APPLYING PRESSURIZED DRILLING FLUID FROM SAID DRILL PIPE TO SAID PISTON MEANS AND THE LOWER PORTION OF SAID CYLINDER MEANS; AND VALVE MEANS ADJACENT SAID PISTON MEANS AND SAID DRIVING MEANS, THE LOWER PORTION OF SAID DRIVING MEANS HAVING PORT MEANS ADJACENT SAID VALVE MEANS, SAID VALVE MEANS BEING MOVABLY MOUNTED ADJACENT SAID LOWER PORTION TO SHIFT DRILLING FLUID FLOW FROM THE LOWER PORTION OF SAID CYLINDER MEANS. 